To a load such as a power amplifier connected to an electronic device such as an electronic control unit (ECU) mounted on a vehicle, a voltage is applied by a regular power supply connected to the electronic device via a wire harness. The electronic device includes a circuit board having a shunt resistor, a current sense amplifier, a microcomputer, and the like, and a case within which the circuit board is provided.
The shunt resistor is arranged between the regular power supply and the load in order to monitor the value of current flowing in the load (for example, Japanese Patent Application Laid-Open No. 2015-123846). The current sense amplifier amplifies the voltage between both ends of the shunt resistor corresponding to the value of current flowing in the load, and outputs the amplified voltage to the microcomputer. The microcomputer uses the voltage amplified by the current sense amplifier, as a control parameter.
Recently, a demand that such electronic devices be downsized has been increasing. If a connector to be electrically connected to the shunt resistor is installed on the circuit board, instead of installing the shunt resistor on the circuit board, and the shunt resistor is fixed with screws, it is possible to downsize the electronic device.